It has come to this: Critics are calling Donald Trump crazy, and he’s calling Hillary Clinton the devil.

Most. Bizarre. Campaign. Ever.

Now Trump didn’t directly call his opponent Satan, although a Google search brings up images of HRC with horns or a pitchfork. He said at a rally in Pennsylvania that Bernie Sanders, in endorsing his rival, “made a deal with the devil. She’s the devil.” A pretty common phrase, but one that should be avoided in a presidential campaign. How do you escalate from the gates of hell? 

But the latest media assault on Trump isn’t just colloquial, as in, hey, the guy is acting nuts lately. Some pundits are flat-out questioning his sanity.

This new effort to put Trump on the couch follows his war of words with Khizr Khan, the Muslim father whose son was killed in Iraq and who denounced the nominee at the Democratic convention.

Now it’s fair to question whether Trump overreacted to Khan’s speech, whether he should have brushed it off, whether he fueled the story, whether it makes sense for a presidential candidate to be debating sacrifice with a couple who lost their son in wartime.

But Trump’s detractors don’t stop there.

Gene Robinson, the liberal Washington Post columnist and MSNBC contributor, felt compelled to declare:

“I am increasingly convinced that he’s just plain crazy.”

Leaving aside Trump’s policies, Robinson writes, “at this point, it would be irresponsible to ignore the fact that Trump’s grasp on reality appears to be tenuous at best.” He adds: “What kind of man has so little empathy for a grieving mother’s loss? Is that normal? Is it healthy?”

Robinson appeared yesterday on MSNBC’s “Morning Joe,” and Joe Scarborough—who had a friendly relationship with Trump during the primaries—went off on him:

“I’ve known him for a decade. I’ve never seen him act like this before,” the former GOP congressman said. “It’s unhinged, it’s not the Donald Trump I’ve known for over a decade.”

Scarborough said he has been talking to plenty of Republicans and conservatives, “and everybody was asking me about his mental health.”

There are others. Foreign policy expert Robert Kagan, also writing in the Post, says: “One wonders if Republican leaders have begun to realize that they may have hitched their fate and the fate of their party to a man with a disordered personality.”

So: A businessman who beat 16 other GOP candidates, including governors, senators and a Bush, to win the nomination, is off his rocker?

A guy who built a successful business and global brand based on his last name is a nutjob?

A performer who created a reality TV show that was a hit for NBC for 14 years is a loony tune?

And how is this screwball running a competitive race with a former first lady, senator and secretary of State? Post-convention polls are giving Clinton a lead of 6 to 9 points, but Trump is still within striking distance, especially in key swing states.

Trump, for his part, has been assailing the “dishonest people” of the press, saying at a rally:

“We are going to punch through the media. We have to! The New York Times is totally dishonest. Totally dishonest. The Washington Post has been a little bit better lately but not good….

“And CNN. CNN is like all Trump all the time. All Trump all the time. You walk out of an interview and you say, 'that was a good interview' and then you get killed for the rest of the weekend. So they are so biased toward Crooked Hillary.”

Some of this has been bubbling up for awhile, on the right as well as the left. The Weekly Standard’s Steve Hayes wrote this in late July:

“Yes, Donald Trump is crazy. And, yes, the Republican party owns his insanity.” Hayes was writing about Trump linking Ted Cruz’s father to Lee Harvey Oswald, saying, “This isn't the behavior of a rational, stable individual.”

And Salon carried this headline: “Maybe Donald Trump has really lost his mind: What if the GOP frontrunner isn’t crazy, but simply not well?” That was back in April. But now it’s growing louder.

The Democrats have intensified their effort to marginalize Trump as a dangerous and dangerously unfit candidate, as we saw in Philadelphia. And now we’re in mental health territory.

The price of running for president is opening your entire life to fierce scrutiny: your judgment, your policies, your background, your temperament. All that serves as a test of how you’d handle the pressures of the presidency.

But arguing that Donald Trump doesn’t have all his mental faculties? That’s crazy.

Howard Kurtz is a Fox News analyst and the host of "MediaBuzz" (Sundays 11 a.m. and 5 p.m. ET). He is the author of five books and is based in Washington. Follow him at @HowardKurtz. Click here for more information on Howard Kurtz.